A prospective assessment of reports of drinking to self-medicate mood symptoms with the incidence and persistence of alcohol dependence

IMPORTANCE Mood disorders and alcohol dependence frequently co-occur. Etiologic theories concerning the comorbidity often focus on drinking to self-medicate or cope with affective symptoms. However, there have been few, if any, prospective studies in population-based samples of alcohol self-medication of mood symptoms with the occurrence of alcohol dependence. Furthermore, it is not known whether these associations are affected by treatment or symptom severity. OBJECTIVE To evaluate the hypothesis that alcohol self-medication of mood symptoms increases the probability of subsequent onset and the persistence or chronicity of alcohol dependence. DESIGN Prospective study using face-to-face interviews-the National Epidemiologic Survey on Alcohol and Related Conditions. SETTING Nationally representative survey of the US population. PARTICIPANTS Drinkers at risk for alcohol dependence among the 43 093 adults surveyed in 2001 and 2002 (wave 1); 34 653 of whom were reinterviewed in 2004 and 2005 (wave 2). MAIN OUTCOMES AND MEASURES Association of alcohol self-medication of mood symptoms with incident and persistent DSM-IV alcohol dependence using logistic regression and the propensity score method of inverse probability of treatment weighting. RESULTS The report of alcohol self-medication of mood symptoms was associated with an increased odds of incident alcohol dependence at follow-up (adjusted odds ratio [AOR], 3.10; 95%CI, 1.55-6.19; P = .002) and persistence of dependence (AOR, 3.45; 95%CI, 2.35-5.08; P < .001). The population- attributable fraction was 11.9% (95%CI, 6.7%-16.9%) for incident dependence and 30.6%(95%CI, 24.8%-36.0%) for persistent dependence. Stratified analyses were conducted by age, sex, race/ethnicity, mood symptom severity, and treatment history for mood symptoms. CONCLUSIONS AND RELEVANCE Drinking to alleviate mood symptoms is associated with the development of alcohol dependence and its persistence once dependence develops. These associations occur among individuals with subthreshold mood symptoms, with DSM-IV affective disorders, and for those who have received treatment. Drinking to self-medicate mood symptoms may be a potential target for prevention and early intervention efforts aimed at reducing the occurrence of alcohol dependence.